1. Field of the Invention
The present invention relates generally to a processing apparatus and a processing method, each using a processing liquid. More specifically, the invention relates to a processing apparatus and method for supplying a liquid chemical or the like serving as a processing liquid to objects to be processed, such as semiconductor wafers or glass substrates for LCDs, to carry out a process, such as wet cleaning.
2. Description of the Related Art
In typical processes for producing semiconductor devices and LCDs, processing apparatuses and methods using processing liquids have been widely adopted in order to remove resists which adhere to objects to be processed (which will be hereinafter referred to as xe2x80x9cwafers or the likexe2x80x9d), such as semiconductor wafers or glasses for LCDs, and residues, such as polymers, which adhere to the surfaces of the wafers or the like after drying processes.
In conventional processes of this type, a cleaning method for reusing a processing liquid, such as an expensive chemical, which has been used for a process, as a recycle liquid to effectively utilize the processing liquid is known.
In a method using this recycle liquid and a new processing liquid, two kinds of tanks for storing therein the new processing liquid and the recycle liquid are prepared. After the recycle liquid is supplied to a processing chamber in the early part of a process to carry out a primary process for wafers or the like, the new processing liquid is used for carrying out a secondary process, so that the processing liquids are effectively utilized.
However, in a conventional process of this type, it is required to provide two kinds of tanks for storing therein the new processing liquid and the recycle liquid. It is also required to equip each of the tanks with apparatuses, such as a temperature controller and a supply pump, and to arrange supply pipe-lines. Therefore, there are problems in that spaces for providing the tanks, spaces for providing the apparatuses, such as the temperature controller and the supply pump, and piping spaces are not only increased to increase the size of the whole apparatus, but the apparatus is also expensive.
It is therefore an object of the present invention to eliminate the aforementioned problems and to provide a liquid processing apparatus and method capable of scaling down the apparatus by decreasing spaces for a plurality of tanks for storing therein processing liquids, which are supplied to a processing chamber, and spaces for piping or the like, and capable of effectively utilizing the processing liquids.
In order to accomplish the aforementioned and other objects, according to one aspect of the present invention, there is provided a liquid processing apparatus comprising: a processing chamber for processing an object to be processed, with a processing liquid; a processing liquid tank for storing therein the liquid, the processing liquid tank having an external tank and an internal tank which is housed in the external tank; a supply pipe-line for supplying the liquid to the chamber from the external tank and the internal tank; and a return pipe-line for returning the liquid from the chamber to the external tank.
According to this processing apparatus, the processing liquid used for the process can be stored in the internal tank and external tank of the processing liquid tank, and the processing liquid in the external tank can be supplied to the processing chamber to carry out the process. Then, the processing liquid used for the process can be returned to the external tank, and thereafter, the new processing liquid in the internal tank can be supplied to the processing chamber. Thus, the process, which has conventionally required a plurality of processing tanks, can be carried out by a single processing liquid tank. Therefore, the installation space for providing the processing liquid tank and the piping space for providing the pipe-lines can be decreased, so that the size of the apparatus can be decreased.
According to the same aspect of the present invention, there is also provided a liquid processing apparatus comprising: a processing liquid tank for storing therein the processing liquid for processing an object to be processed, the processing liquid tank having an external tank and an internal tank which is housed in the external tank; and a heater surrounding the external tank.
According to this processing apparatus, the processing liquids in the external and internal tanks can be heated and heat-retained by a single heater.
Preferably, this processing apparatus further comprises: a heating temperature sensor for detecting a heating temperature of the heater; an external tank liquid temperature sensor for detecting the temperature of the processing liquid in the external tank; and a temperature controller for controlling the temperature of the processing liquid in the external and internal tanks, on the basis of detected values of the heating temperature sensor and external tank liquid temperature sensor.
Thus, the temperatures of the processing liquids in the external and internal tanks can be controlled so as to be appropriate temperatures.
In this case, the heater preferably has a plurality of heating bodies separated from each other in circumferential directions of the external tank, and adjacent two of the heating bodies are preferably connected to each other so as to be capable of approaching and going away from each other in the circumferential directions.
Thus, the heating efficiency can be improved by causing the heating bodies to follow the expansion and contraction of the external tank depending on the heating by means of the heater.
Preferably, the above described processing apparatus further comprises: a processing liquid supply source for supplying the liquid; a processing liquid pipe-line for supplying the liquid from the processing liquid supply source to the internal tank; and an overflow pipe-line for supplying a part of the liquid, which overflows the internal tank, to the external tank.
According to this processing apparatus, when the external and internal tanks are empty, the processing liquid from the processing liquid supply source can be stored in the internal tank, and can overflow the internal tank to be stored in the external tank.
The external tank may have a barrel portion and an opening portion provided in an upper portion of the barrel portion. Preferably, in this case, and a gap size between the external tank and the internal tank at the opening portion is preferably greater than half inches, and designed so that a cross section of the external tank at the opening portion is smaller than a cross section of the external tank at the barrel portion.
Thus, it is possible to decrease the area of the processing liquid in the external tank contacting a gaseous phase to inhibit the chemical reaction and deterioration of the processing liquid, so that it is possible to maintain the quality and performance of the processing liquid.
Preferably, in this case, the processing apparatus further comprises: a purge gas supply pipe-line, which is connected to said opening portion of said external tank, for supplying a purge gas to said external tank; and a vent pipe-line for exhausting said purge gas which is supplied to said external tank by said purge gas supply pipe-line.
Thus, it is possible to prevent the processing liquid stored in the external tank from being exposed to outside air to vary atmosphere.
The supply pipe-line preferably comprises: a first supply pipe-line connected to the external tank; a second supply pipe-line connected to the internal tank; a main supply pipe-line, into which the first and second supply pipe-lines are combined; a supply pipe-line switching apparatus for switching a pipe-line, which is communicated with the main supply pipe-line, between the first supply pipe-line and the second supply pipe-line; and a supply pump provided in the main supply pipe-line.
Thus, the external and internal tanks can share a part of the supply pipe-line and the supply pump, so that it is possible to decrease the size of the apparatus and to lower the price of the apparatus.
Preferably, in this case, the processing apparatus further comprises a circulating pipe-line connecting a discharge side of the supply pump in the main supply pipe-line to the external tank.
By circulating the processing liquid in the external tank by means of the circulating pipe-line during the waiting for the supply of the processing liquid, the processing liquid can be immediately supplied to the processing chamber when the supply is started. Therefore, it is possible to improve the time efficiency of the process. By circulating the processing liquid in the external tank, it is possible to enhance the uniformity of the temperature distribution of the processing liquid, and to enhance the uniformity of the temperature distribution of the processing liquid in the internal tank, which is heat-exchanged between the processing liquids in the external and internal tanks. Thus, it is possible to improve the reliability and performance of the process.
Preferably, in this case, the supply pipe-line further comprises: a bypass pipe-line connected to the discharge side of the supply pump in the main supply pipe-line so as to bypass the main supply pipe-line; a bypass switching apparatus for switching a flow of the processing liquid from the supply pump between the main supply pipe-line and the bypass pipe-line; and a filter provided in the bypass pipe-line.
Thus, the supply pipe-line can be switched between the main supply pipe-line and the bypass pipe-line with respect to, e.g., the new processing liquid and the recycle liquid which has used for the process. In this case, the supply pipe-line can be switched so that only the recycle liquid having used for the process flows through the bypass pipe-line to be filtered by the filter, so that it is possible to increase the life of the supply pipe-line and so forth.
According to another aspect of the present invention, there is provided a liquid processing method for supplying a processing liquid from a processing liquid tank, which has an external tank and an internal tank housed in the external tank, to a processing chamber to carry out a process with respect to an object to be processed, with the processing liquid in the processing chamber, the processing method comprising: a step of storing a processing liquid, which is supplied from a processing liquid supply source, in the internal tank, and storing a part of the liquid, which overflows the internal tank, in the external tank; a first processing step of supplying the part of the liquid in the external tank to the chamber to carry out the process; a step of returning the part of the liquid, which has been used for the process at the first processing step, to the external tank; and a second processing step of supplying the liquid in the internal tank to the chamber after the first processing step, to carry out the process.
According to the same aspect of the present invention, there is also provided a liquid processing method for supplying a processing liquid from a processing liquid tank, which has an external tank and an internal tank housed in the external tank, to a processing chamber to carry out a process with respect to an object to be processed, with the liquid in the chamber, the processing method comprising: a step of storing a recycle processing liquid, which has been used for the process at least once in the chamber, in the external tank; a recycle liquid processing step of supplying the recycle processing liquid in the external tank to the chamber to carry out the process; a new liquid processing step of supplying the new processing liquid stored in the internal tank to the chamber after the recycle liquid processing step, to carry out the process.
Preferably, in the above described processing method, the liquid in the external tank is heated by a heater surrounding the external tank, the liquid in the internal tank is heated by a conductive heat from the liquid in the external tank, and a heating temperature of the heater and a temperature of the liquid in the external tank are detected to control a temperature of the liquid in the external and internal tanks, on the basis of detected values of the heating temperature and the liquid temperature.